An international standard which defines the physical and electrical interface specifications for the interchangeability of memory and input/output cards was introduced by Personal Computer Memory Card International Association (PCMCIA) jointly with the Japanese Electrical Industry Association (JEIDA) in September of 1991. In addition, a specification referred to as an Exchangeable Card Architecture (ExCA) specification, Dec. 20, 1991, has been issued by Intel Corporation of Santa Clara, Calif. The ExCA document describes specifications which manufacturers may use to provide interfaces which are ensured of allowing the memory and input/output cards for portable personal computers of different manufacturers to be interchanged.
A socket design to these specifications allows integrated circuit (IC) cards, such as modem and memory cards, to be attached, used, and removed interchangeably in the same socket. Computer systems typically include at least one socket recessed within the computer, such that the inserted components (e.g., modem, LAN, etc.) are protected by the body of the computer surrounding the interface circuitry (i.e., socket) in which the components are to be coupled.
The PCMCIA standard includes a maximum warpage specification which requires that the physical structure of IC cards must undergo and pass a number of stringent mechanical tests. First, the IC card must pass a shock and vibration test in which the IC card is subjected to shock and vibration to determine if the integrity of the physical structure of the IC card is violated. Second, the IC card is subjected to a bend test in which a first end of the IC card is clamped such that most of the IC card is suspended above a surface. A static load is then placed at the opposite end to determine the extent to which the static load will warp the physical structure of the IC card. Currently, the static load is equal to 4.4 pounds. A third test is the torque test in which the IC card is again clamped as described for the bend test. Torque is applied to the unclamped end such that the IC card is twisted. Currently, the maximum torque is 12.6 kg-cm and the maximum angel of twisting is ten degrees. The torque test is also used to determine the amount of warp.
Typical prior art IC cards have been unable to meet the maximum warpage specification of the PCMCIA standard. This inability to meet the warpage specification results in many types of failures including printed circuit board damage due to flex, frame breakage, the separation or lifting of the cover from the frame, cover deformation, and connector misalignment and movement. A new frame and cover structure for IC cards is therefore needed to better meet the maximum warpage specification of the PCMCIA standard.